How do i stop this downdraft?

[DammitJim]

Hello,

I have an airtight wood-stove in the basement of my house. Apparently i have a negative pressure causing a downdraft in the chimney.

To light the stove i just open the basement window to equalize the pressure, start a fire keeping the stove door open slightly. After 5 to 10 minutes i have a good draft and all is good.

My problem is when i'm not using the stove i get a terrible smell from the chimney.
My local experts have suggested putting an extension pipe on top of the chimney ($500+). with no guarantees it will work. Also available are the draft assisting fans that i could install on the stove pipe or the chimney cap. ($200++). But i don't care for the idea of running a fan day and night to control the smell.

It seems to me the easiest and most cost effective way would be to have an airtight shutoff on the stove pipe between the stove and breach pipe. Unfortunately it appears no one makes such an animal.
I've been thinking of installing a stainless steel blast gate like the ones offered at www.blastgateco.com, but i'm not sure if this will work.

Any help would be appreciated

Thanks,
DammitJim

 

[jtp10181]

Fix the broken house instead of the fireplace which is probably fine...

What is your main heat source? Is it a forced air system?

ALso, you should add an outside air kit on your stove as well.

 

[Fire Bug]

Jim,
If you have a negative pressure problem and you have an older type stove where you can get at the stove pipe from inside the firebox, preheat your stove pipe by lighting a newspaper rolled up and holding it at the stove pipe opening in the stove. This will reverse the draft and create a stronger draft.
Do this along with cracking a door or window open to assits in this process.
As far as the smell goes, I don't know what to recomend unless you block the stove pipe off with insulation in the off season.
John

 

[webbie]

Sounds like you and everyone else have the score!

The reversing chimney will NOT be solved by extension. This is a function of the "stack effect" and therefore negative pressure...but not the same kind that a kitchen or bath fan produces. In other words, providing make up air will not usually solve these problems.

An insulated stainless steel liner would go a long way, but no guarantee there either. A pipe or chimney top draft inducer will also do the job (field, tjerlund).

All in all, you might be best with FB's advice- install a tee or another way in...as close to the chimney as possible, and stuff some balled up paper in there to get things started, then light the load.

 

[Todd]

Outside make up air or an outside air hooked up directly to the stove would solve your problem. Check this out. (broken link removed to http://www.condar.com/asv.html)

I tried the Condar air supply ventilator in my basement next to my stove and it helped some, but I think its not much better than an open window. A few days ago I installed a direct hook up to the stove and it seems to work much better. Less drafts and house seems to heat up quicker and retain the heat better.

 

[scottgen20]

I've got a Field Controls Chimney Top Draft inducer that I picked up off Ebay new for about $350. It is basically a heavy chimney cap, all stainless, with a heavy duty fan built in.

I know that the general concensus is to solve an issue in a non-mechanical way, but I've had only good experiences with the draft inducer.

My chimney is marginal (15-16") which has made my Jotul F100 a bear to start in past years. I've also experienced the "chimney" smell in my living room. I went so far as to remove the top baffle of the stove and shove insulation into the pipe when I wasnt using the stove.

I'm not sure if it's the shape of the new draft inducer cap, but I rarely get the "chimney" smell in the house when the stove is not running. If I do, I just flip the switch and the issue is resolved. The fan motor is no larger than a bathroom fan, so electricity use is minimal.

It also makes lighting the stove a breeze...(literally). I basically turn on the fan prior to starting off the fire. I leave the fan on until the load gets ingulfed - usually about :30 minutes and then turn off the fan and natural draft takes over. This is my first year with the inducer and I couldnt live without it. Prior to having the inducer, it was a huge chore getting a fire started and it usually ended in me cursing the chimney.

I could have added to the chimney height, but it's a fieldstone chimney and I've got hills surrounding my house -- so the cost of extending without a guarantee vs the cost of a mechanical means which guaranteed success was a no-brainer.

You've got the opposite problem of a chimney feeding a basement stove, but it would resolve your issue as well..

I know there are other manufacturers including Exhausto which makes an excellent if pricey product.

 

[Cazimere]

I've got a Field Controls Chimney Top Draft inducer that I picked up off Ebay new for about $350. It is basically a heavy chimney cap, all stainless, with a heavy duty fan built in.

Do you have a lightning rod ?

 

[Michael6268]

Sounds like you are more concerned with the downdraft when you are not using the stove. Probably the best way to remedy this is with a "top mounted damper". It could be totally closed off when not using the stove resulting in no downdraft or smell.

 

[Michael6268]

You could also try a stove pipe damper. While they dont seal the pipe completely when fully closed, it would help. Along with closing all of you stove air controls too.

 

[DammitJim]

Thanks for all the advice guys.

I think in the long run my best bet is to go with the chimney top damper or draft inducer. Supplying a fresh air supply to the stove or a ventilator in the basement would solve one problem (bad smell from chimney) but create another (cold draft in the basement).

I think for the rest of this season i will take the admins. advice and install a tee in the stove pipe between stove and chimney. Not to help light the fire but so when the stove is not in use i can remove the cap from the tee and stuff some insulation in the pipe to block the downdraft.

Again, thanks for all the replies

Sean